Have you saved any Logins data in Firefox 69 on Windows 10 before doing that copy'n'paste?

If so, my advice is the create a new Profile and do that copy'n'paste again in the new Profile.

I have tried but its as though Firefox turns its nose up at its older self, having tried deletion, re-install fresh coping etc only get my bookmarks no passwords to move over.

Thought about putting another browser on my XP (if one would want to due to age) so it imports things then use it as some go-between on a later version of itself under 10.

Decided to go the other longer route, which you will need to make sure you have a printer loaded with ink and paper first!

On XP find the last version of the Add-on "Password Exporter" held on some sites (will only work on older Firefox) install then use it to export to a .XML file on your computer.

Not wanting to use those internet converters to have my details splattered about, I used my old TurboView & Convert software to read then make it into a HTML file.

This can then be read even by my old MS Office XP Pro suite (2003) with Word printing this out in Landscape (or it will be a pain to read) at least a font size 12 and your passwords will arrive.

Started filling in my most urgent bookmarks with help with some, from some computers & my newer 10 finding and filling in my usernames cutting down on some work during this rebuild. DO NOT FORGET TO SHRED IT AFTERWARDS!

Puzzles me after all these years of getting a bit of software to play with only giving scant details of who you are so you can sure "they" only have an email address for you and nothing else (so if they are hacked your details are limited) now you need to fill in more info.........

Ah well progress they say...........

To copy the logins from XP you need these two files: logins.json and key3.db You need to remove a possible existing key4.db file in the profile folder to make Firefox fallback to key3.db for the key file and create a new key4.db file. Note that you lose all currently stored passwords, so make sure to write your passwords down if you've already stored any. Firefox should be closed when you copy these file to the current Firefox profile folder.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/Profiles

You can copy files like these with Firefox closed to the current profile folder to recover specific data.

• bookmarks and history: places.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

See also:

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile